A247193 a(n) = gcd(n!, Fibonacci(n)).

1, 1, 2, 3, 5, 8, 1, 21, 2, 5, 1, 144, 1, 13, 10, 21, 1, 136, 1, 165, 26, 1, 1, 46368, 25, 1, 34, 39, 1, 440, 1, 21, 2, 1, 65, 139536, 1, 37, 2, 1155, 1, 3016, 1, 129, 170, 1, 1, 4358592, 13, 275, 2, 3, 1, 136952, 5, 55419, 74, 1, 1, 10066320, 1, 1, 442, 987, 5, 8, 1, 201, 2, 20735, 1, 44930592, 1, 73, 3050, 111, 13, 8, 1, 2225685

Offset: 1

Author

Carlos Eduardo Olivieri, Nov 24 2014

Keywords

• nonn
• easy

Examples

			For n = 8: GCD(8!, Fibonacci(8)) = 21.
		

Links

• Ivan Neretin, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000045, A000142, A250445, A069180.

Programs

Maple

seq(igcd(n!, combinat:-fibonacci(n)), n=1..100); # Robert Israel, Nov 24 2014

Mathematica

a[n_] := GCD[n!, Fibonacci[n]];
Table[a[n], {n, 1, 300}]

PARI

vector(100,n,gcd(n!,fibonacci(n))) \\ Derek Orr, Nov 24 2014

Formula

a(n) = gcd(n!, Fibonacci(n)).

a(A069180(n)) == 1. - Michel Marcus, Nov 25 2014